}
    try {
      TopKSelector.least(-1, Ordering.natural());
      fail();
    } catch (IllegalArgumentException expected) {
    }
    try {
      TopKSelector.greatest(-1, Ordering.natural());
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testZeroK() {
    TopKSelector<Integer> top = TopKSelector.least(0);
    for (int i = 0; i < 10; i++) {
      top.offer(i);